The present invention relates to an apparatus for dispensing individual plastic fasteners from fastener stock.
Plastic fasteners of the type having a cross-bar at one end, a paddle at the other end and a thin filament or cross-link connecting the two ends are well known in the art and are widely used in commerce to attach labels, price tags or other items to articles in a manner which minimizes the risk of inadvertent detachment therefrom. Typically, such plastic fasteners are manufactured in the form of a supply of fastener stock, the fastener stock being produced by molding or stamping from flexible plastic materials, such as nylon, polyethylene, and polypropylene.
In one well known type of fastener stock, the cross bar end of each fastener is connected to a runner bar to form a clip of fasteners. In another known type of fastener stock, often referred to simply as ladder stock, a pair of elongated side members are interconnected by a plurality of cross links or filaments. One of the side members is shaped to define a plurality of cross bars which are joined together by short severable connectors, the connectors being defined by indentations or notches formed along the side member. The other side member is shaped to define either a plurality of paddles or cross bars which are similarly joined together by short severable connectors.
The dispensing of individual fasteners from fastener stock is often accomplished with an apparatus commonly referred to as a tagger gun. Typically, a tagger gun is a hand held trigger operated device which is constructed to accept fastener stock. Tagger guns usually include a mechanism for feeding the cross bar end of a fastener into a hollow needle at the front end of the gun and a mechanism for pushing the cross bar end of the fastener that has been fed into the hollow needle out through the tip of the hollow needle. Some tagger guns are manually operated while other tagger guns are powered by an electric motor or a pneumatic device.
Tagger guns have been developed and are in use with both of the above described types of fastener stock.
For example, in U.S. Pat. No. 4,456,123 to D. B. Russell, which is incorporated herein by reference, there is disclosed an apparatus for dispensing fasteners which is manufactured and sold by AVERY DENNISON CORPORATION® of Pasadena, Calif. as the SYSTEM 1000® SWIFTACHER® Tool. The apparatus can be used to store, feed and dispense fastener stock of the type which includes a plurality of connected fasteners, each fastener comprising a flexible filament and a transversely disposed endear at one end, end-bars of adjacent fasteners being joined end-to-end by severable connectors at a portion of their peripheries. The apparatus comprises a hollow casing and a dispensing needle mounted to the casing, the needle having a longitudinal bore for slidably receiving the end-bar and a slot communicating with the longitudinal bore slidably receiving the filament. The apparatus also comprises means for advancing a fastener from a first position remote from the needle bore to a second position adjacent the rear end of the bore with the end-bar transversely disposed to the longitudinal axis of the bore, means for aligning the end-bar with the bore and means for dispensing the end-bar through the bore.
Although well known and widely used in commerce, tagger guns of the type described in U.S. Pat. No. 4,288,017 to D. B. Russell suffer from a few notable drawbacks.
As a first drawback, tagger guns of the type described in U.S. Pat. No. 4,288,017 to R. B. Russell include a single, spring activated slide which can cause jamming in the tagger gun upon partial compression of the trigger, which is highly undesirable. Specifically, the single, spring activated slide assists in both aligning the end-bar of a first fastener from the fastener stock into parallel alignment within the longitudinal axis of the needle and indexing a second successive fastener from the fastener stock so that its end-bar is positioned at the rear end of the needle at an angle with respect to the longitudinal axis of the needle. As a result, it has been found that, if the user fails to fully compress the tagger gun trigger, the slide will index the second fastener at the rear end of the needle before the first fastener is fully ejected from the hollow needle. Because the second fastener will be aligned within the hollow needle before completion the forward ejection stroke, a partial compression of the tagger gun trigger will result in both the first and second fasteners disposed within the hollow needle at the same time, thereby creating a serious risk of jamming, which is highly undesirable.
As a second drawback, tagger guns of the type described in U.S. Pat. No. 4,288,017 have a relatively large number of different components, many of which are spring loaded. Accordingly, it has been found that such tagger guns are relatively expensive, time-consuming and difficult to manufacture, which is highly undesirable.
As a third drawback, tagger guns of the type described in U.S. Pat. No. 4,288,017 utilize a fairly complicated process for advancing the fastener to the rear of the needle, rotating the end-bar of the fastener into alignment within the needle and ejecting the end-bar through the needle, thereby creating a rough and difficult trigger stroke, which is highly undesirable.